spec: Fix building with new cmake macros

= changelog =
resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1863376

Signed-off-by: Nicola Sella <nsella@redhat.com>

createrepo_c.spec

@@ -1,5 +1,7 @@
 %global libmodulemd_version 2.3.0
 
+%define __cmake_in_source_build 1
+
 # Bash completion (we need different approach for RHEL-6)
 %if 0%{?rhel} == 6
 %global bash_completion %config%{_sysconfdir}/bash_completion.d/createrepo_c.bash
@@ -36,7 +38,7 @@
 Summary:        Creates a common metadata repository
 Name:           createrepo_c
 Version:        0.15.11
-Release:        3%{?dist}
+Release:        4%{?dist}
 License:        GPLv2+
 URL:            https://github.com/rpm-software-management/createrepo_c
 Source0:        %{url}/archive/%{version}/%{name}-%{version}.tar.gz
@@ -260,6 +262,9 @@ ln -sr %{buildroot}%{_bindir}/modifyrepo_c %{buildroot}%{_bindir}/modifyrepo
 %endif
 
 %changelog
+* Fri Aug 07 2020 Nicola Sella <nsella@redhat.com> - 0.15.11-4
+- spec: Fix building with new cmake macros
+
 * Sat Aug 01 2020 Fedora Release Engineering <releng@fedoraproject.org> - 0.15.11-3
 - Second attempt - Rebuilt for
   https://fedoraproject.org/wiki/Fedora_33_Mass_Rebuild